The present invention is particularly applicable as a self-sustained composite sheet stock for reconstituting frozen pizza, such as elongated, rectangular sections of bread topped with pizza constituents and frozen individually. This well known product is to be reconstituted by subsequent thawing and baking by the ultimate consumer. The invention will be described with particular reference to this mass produced, consumer food product; however, it is appreciated that the invention has substantially broader applications and may be used for heating or reconstituting various food products.
One of the most popular frozen entrees is pizza constructed of a generally rectangular segment of a lower farinaceous crust layer in the form of a French bread and an upper topping layer including a mixture of various substances generally including cheese, tomato sauce and meat. The topping materials are selected to provide a variety of products for the consuming public. In the preferred embodiment, the bread is baked, cut down the middle and quartered into rectangular segments. The topping is added in an uncooked, usually frozen condition. These individual bread segments or sections are sold to the public in a frozen condition for extending their shelf life. Such layered food products or articles, for the best consumer acceptance from a taste and texture sense, should be thawed and then baked by some heating appliance into the desired reconstituted texture and condition. Due to the starch and other characteristics of the lower layer of this food substance, it has been found that high quality reconstitution can be accomplished only by heating in a convection oven. Attempts to reconstitute this type of food or pizza by microwave heating, a concept now popular with and demanded by the public, have not been commercially satisfactory. Consequently, manufacturers who have introduced microwave reconstituted pizza have had to compromise on ultimate quality. A consumer was faced with the dilemma of purchasing a microwavable pizza having a compromised ultimate quality or a high quality pizza of the type reconstituted only in a convection oven. The standard convection oven produced a crunchy, high quality crust having a dough which is crisp and a topping which is cooked to duplicate freshly purchased, hand made pizza.
When attempting to bake, cook or otherwise reconstitute frozen pizza in a microwave oven, cooking time was definitely decreased; however, the pizza lost its bread texture, resulting in almost no crispness or crunchiness. Generally the topping material was overcooked while attempting to make the crust crisp. This process produced a somewhat flaccid product which must be held some time before the pizza is self-sustaining for normal consumption and manual manipulation. Such delay in eating the pizza to decrease its flaccidity, caused the crust to become hard and brittle. Such condition is clearly unacceptable to a manufacturer of mass produced frozen pizza who was concerned about its reputation in the marketplace. Further, the product generally lost its resiliency, turned leathery and caused the hot sauces forming part of the topping to migrate into the prebaked bread cells. This further detracted from consumer acceptance of the reconstituted pizza. The consuming public was provided with the unacceptable dilemma of choosing a low quality product or a high quality product based upon the type of heating desired by the consumer.
To decrease the disparity between microwave reconstituted pizza and convection oven reconstituted pizza, some producers have attempted to prefry a standard pizza crust so the crust would be preset before being frozen. This procedure somewhat reduces the shelf life of the frozen product and has a tendency to increase its fat content. Further, such procedure is known to affect the ultimate flavor of the reconstituted product when using standard pizza crust; therefore, some producers employ added flavors to mask such flavor changes resulting from prefrying the standard pizza crust to increase the crust quality of a microwave reconstituted pizza. Such procedures are not acceptable to companies valuing high reputation or ultimate quality of their reconstituted food entrees.
In view of this situation, one of the most successful pizza products is pizza formed from baked and sliced French bread covered with uncooked ingredients and reconstituted in a convection oven instead of standard crust pizza reconstituted by a microwave oven.
To alleviate the difficulties experienced in microwave reconstitution of pizza, especially using standard crust, special packages have been developed. An early concept is suggested in Turpin U.S. Pat. No. 4,190,757 that utilized a lower susceptor sheet spaced from the bottom wall of the microwave oven onto which the lower farinaceous crust portion of the pizza was supported so that the crust portion was heated to a high temperature causing browning and crispness adjacent the lower surface of the crust. This early suggestion has now been employed by certain manufacturers of pizza in the form of a lower plate, boat or platform onto which the pizza on a standard crust is placed for reconstitution in a microwave oven. This procedure, although having some advantages, was not successful until the development of the material not suggested in Turpin U.S. Pat. No. 4,190,757; but, disclosed generally in Seiferth U.S. Pat. No. 4,641,005. When the microwave susceptor material became available in sheet stock at a low cost such as disclosed generally in Seiferth U.S. Pat. No. 4,641,005, such susceptor sheet material was used to construct the previously unsuccessful plates, boats and/or platforms suggested for reconstitution of frozen pizza. By using this new sheet susceptor material, some crispness is obtained at the lower level of the pizza crust: however, the crust remained flaccid and the sauce, forming a constituent of the topping, was overcooked because the topping was exposed to only microwave heating acting upon the many components of the topping. The remainder of the crust layer was heated in a nonuniform manner to result in a soft crust. Frozen pizza reconstituted by a microwave procedure suggested in Turpin U.S. Pat. No. 4,190,757 and employing a microwave susceptor sheet of the general type disclosed in Seiferth U.S. Pat. No. 4,641,005 is still substantially unacceptable for quality reconstitution of frozen pizza of the type using standard crust. When using a bread base for the pizza, the bread was flaccid. The lower surface of the crust, in both instances, became brown or crisp; however, the rest of the crust was still extremely crunchy. Thus, even use of the new microwave susceptor sheet material had the disadvantages of prior attempts to reconstitute pizza using standard unbaked crust or a bread base in a microwave oven. Even the use of a microwave susceptor sheet, which is well known, as a plate, platform and/or boat on or spaced from the lower wall of the microwave oven, as suggested and attempted by some manufacturers, has been unacceptable. Manufacturers have gone back to the prebaked, standard crust concept for pizza to be cooked by a microwave oven. Some of these manufacturers have packaged the pizza in a vacuum package to increase shelf life which, as mentioned before, is reduced when standard pizza crust is precooked.
In summary, even with the tremendous activity and development work by most frozen food manufacturers and producers of susceptor sheet stock all attempting to microwave reconstituted frozen pizza, there has been no successful heating arrangement on the market that produces an acceptable reconstitution procedure for frozen pizza or similar layered, curst supported food products.